The invention relates to micro-miniature jet nozzle fabrication components and in particular to semiconductor construction and mounting techniques for miniature jetting devices.
Micro-miniature jetting devices are suitable for a variety of applications including hand-held ink jet printers, ink jet highlighters, ink jet air brushes, and delivery of controlled quantities of medicinal fluids and purified water to precise locations. One of the challenges to providing such micro-miniature jetting devices on a large scale is to provide a manufacturing process that enables high yields of high quality jetting devices. While ink jet manufacturing techniques are well known, they do not lend themselves to low cost production techniques because of the exacting nature of the product used for ink jet printers. There is a need therefore, for micro-miniature jetting devices which lend themselves to reduced manufacturing costs.
With regard to the foregoing and other objects and advantages the invention provides a jet head box for a semiconductor substrate and nozzle plate containing fluid jet actuators. The jet head box includes an elongate substantially rigid body having a first surface and a second surface opposite the first surface. The body also includes a first recessed portion defining a substrate pocket area in the first surface thereof. At lease one elongate slot extends through the body from the second surface to the first surface in the substrate pocket area. An encapsulant dam is provided adjacent at least one end thereof. A shelf is adjacent the encapsulant dam.
In another embodiment the invention provides a micro-miniature fluid jetting device. The device includes a jet head box having an elongate substantially rigid body. The body has a first surface and a second surface opposite the first surface. A first recessed portion defining a substrate pocket area is provided in the first surface thereof. At least one elongate slot extends through the body from the second surface to the first surface in the substrate pocket area. The body further includes an encapsulant dam adjacent at least one end thereof, and a shelf adjacent the encapsulant dam. A semiconductor substrate and nozzle plate therefor is attached to the first surface of the jet head box in the first recessed portion. Conductive leads are attached to the semiconductor substrate. Contact pads are provided on the conductive leads and semiconductor substrate. An encapsulant for encapsulating the contact pads on the conductive leads and semiconductor substrate is also provided.
In yet another embodiment, the invention provides a method for encapsulating connections between conductive leads and a semiconductor substrate for a micro-miniature fluid jetting device. The method includes the steps of providing a jet head box including an elongate substantially rigid body, the body having a first surface and a second surface opposite the first surface, a first recessed portion defining a substrate pocket area in the first surface thereof, at least one elongate slot extending through the body from the second surface to the first surface in the substrate pocket area, a first jet head box end and an opposing second jet head box end, the body further including an encapsulant dam adjacent at least the first jet head box end, a shelf adjacent the encapsulant dam, and at least one conductive lead adjacent the encapsulant dam and extending onto the shelf. A semiconductor substrate and nozzle plate therefor is attached to the first surface of the jet head box in the first recessed portion thereof. A first end of the semiconductor substrate is connected to the at least one conductive lead. The jet head box is tilted to an angle ranging from about 5 to about 45 degrees relative to a substantially horizontal plane so that the first jet head box end is lower than the second jet head box end. A substantially low viscosity encapsulant material is applied to the conductive lead and first end of the semiconductor substrate. Upon curing, a cured encapsulant material is provided. The cured encapsulant material has a sloped surface extending from the encapsulant dam to the first end of the semiconductor substrate.
An advantage of the invention is that it provides a structure which significantly minimizes the manufacturing costs for micro-miniature fluid jetting devices. For simple fluid jetting applications, substantially all logic and timing circuits are preferably contained on the semiconductor substrate so that only power and ground leads are required to be connected to the substrate. In the alternative, up to about ten leads are attached to the semiconductor substrate for control of fluid jetting. Hence, once the substrate, head box and leads are assembled, the entire assembly may be handled in an environment other than a clean room.
Applications for such micro-miniature jetting devices include, but are not limited to pre-coat applicators for ink jet printers, sterile water spray devices for surgery, lubricating oil spray devices for mechanical equipment, spray cleaners for recording devices, small local fire extinguishers, evaporative coolers, and the like.
Another advantage of the invention is that cleaning of the jetting nozzles is un-hindered by sealants and encapsulants used to protect electrical connections to the micro-miniature jetting device. This advantage is achieved by providing electrical connections to the semiconductor substrate that are on an end of the substrate perpendicular to the jetting nozzles and direction of travel of a cleaning device or wiper blade across the jetting nozzles.